At the present time, most mattress spring core assemblies are manufactured by a spring manufacturer who assembles the springs into a spring assembly. To save space and therefore reduce shipping costs, the spring manufacturer compresses multiple spring assemblies and ties them in a crate. The crates are shipped to a mattress manufacturer, who then uncrates the compressed spring cores, applies a primary insulator to the top and bottom surfaces of the mattress, and then applies conventional padding and upholstery to complete the mattress. In order to keep the mattress spring assemblies straight and avoid the mattresses top and bottom surfaces being permanently canted and distorted as the spring assemblies are compressed for shipment in a crate, there are rods inserted through the spring assemblies during the compression process. These rods function to prevent misalignment of the top and bottom surfaces of the spring assemblies during compression, which rods are then removed after compression and during shipment within the crate.
As an alternative to compression of the spring assemblies for shipment in crates, some spring assemblies are compressed and roll-packed while sandwiched only between separator plies of paper or plastic, which paper or plastic may be either discarded or reused, depending on the nature of the separating materials.
For instance, it is known in the art to roll-pack multiple spring assemblies or units for use in making mattresses by winding disposable paper or re-usable hessian around a mandrel and feeding the spring units successively into the nip between the growing roll and the traveling web material. The spring units are compressed as they are drawn into the roll, and the result is that the roll-packed spring assemblies have a much reduced volume as compared to conventionally stacked spring units.
Prior art roll packing machines compress and wrap spring assemblies in a single web of disposable paper or reusable material which separates the multiple layers of spring assemblies in a roll and maintains the spring assemblies in a compressed state for shipment from a spring manufacturer to a mattress manufacturer. The mattress manufacturer then must unroll the spring units and manually attach an insulator pad to at least the top and usually the top and bottom surfaces of each spring unit before adding conventional padding and upholstery to the unit to complete the mattress. The insulator pads prevent the conventional filling materials such as padding from falling between the wire gaps in the spring assembly. The manual application of these insulator pads is time consuming and costly because it requires an operator manually securing the insulator pads to the spring assemblies with hog rings or other fasteners.
Applicant's U.S. Pat. No. 6,357,209, which is fully incorporated by reference herein, discloses a method of packaging spring units in which at least one layer of insulator material is permanently secured to multiple spring units before the spring units and insulator material are roll packed. The roll packed bedding products are then shipped in a roll to a mattress manufacturer who unrolls them and applies padding or other filling materials before encased each spring unit in a fabric covering.
However, in certain circumstances, a mattress manufacturer may receive a roll of roll packed spring assemblies which do not have any webs of insulator material attached thereto. In such a situation, the mattress manufacturer must unroll the roll packed spring assemblies and subsequently apply at least one web of insulator material to each spring assembly before padding and/or filling materials are added and the product encased in fabric. Heretofore, this process has been manual, an operator hog ringing or otherwise securing at least one web of insulator material individually to each spring assembly. This manual application of the insulator pads is time consuming and costly because among other things, this process requires a skilled, trained operator.
Therefore, it has been one objective of the present invention to provide an automated method of quickly and easily securing at least one web of insulator material to multiple spring assemblies.
It has been a further objective of the present invention to facilitate and ease the manufacture of spring mattresses by a mattress manufacturer.